You can buy a scent kit from Hunter's Specialties @ Wal-Mart for $20. Its comes with a bottle of the spray, laundy detergent, soap, deodarant, earth scent dryer sheets, and one of the bags you are talking about. Its a good deal if you need a couple of the other items as well.

EDIT:

A buddy of mine stores his clothes in a similar manner and hesprinkles some baking soda in the bag and he said it will trap any odors that do get in. He has killed many deer and a couple wallhangers so I guess it works. Anyone else heard of this.